Manipulators



MANIPULAToRs Sept. 24, 1968 3 Sweets-Sheet` 1 Filed Feb, 28, 1966 Y www um mmh v ..u .MMI Q @J mvLw/V///v/ fl l ,u :H.- ,Ul Tl.- l 1V wm @mem/ml@ \umm QQQWS mm NMEMWR Q vm www `/w/M/// R @n 9 5/ s., n., m Fm o v @mw QN QN f Q @33mm l; I L @m Qv Fl E. MAcHoN ETAL 3,402,592

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il @TQ www @www fsm-ons Rod B. I. 'BNmaRY dnluwL.ml-*|wlu mais ATTORNE United States Patent O 3,402,592 MANIPULATORS Edward Machen, Shetield, and Bela Istvan Bathory, Wales, near Shetlield, England, assignors to Davy and United Engineering Company Limited, Sheffield, England Filed Feb. 28, 1966, Ser. No. 539,420 Claims priority, application Great Britain, Mar. 2, 1965, 8,901/65 2 Claims. (Ci. 72--421) ABSTRACT 0F THE DHSCLOSURE This invention relates to manipulators for carrying a workpiece to be forged. When forging in a series of bites it is preferable that the main mass of the manipulator should `move continuously in the direction of forging, and since while the Aworkpiece is gripped by the press tools it cannot move, the peel is mounted on the manipulator car- ICC of the cylinder and having passages opening adjacent the end face of the piston on either side of the projection and opening at the end face of the projection.

An embodiment of a piston and cylinder assembly for powering the peel of the manipulator, in accordance with the invention, will now be described, by way of example only, with reference to the accompanying d-rawings of which:

FIG. 1 is an axial section through a piston and cyl inder assembly in its datum position,

FIG. 2 is a diagrammatic view of the assembly shown at the end of recoil when forging away from the press,

FIG. 3 is a diagrammatic view of the assembly shown with the piston having returned to the datum position from the FIG. 2 position,

FIG. 4 is a diagrammatic view of the assembly shown at the end of the recoil when forging towards the press, and

FIG. 5 is a diagrammatic view of the assembly shown with the piston having almost returned to the datum position from the FIG. 4 position.

The apparatus shown in FIG. 1 is of the kind having a single piston and a single cylinder. A piston rod 12 is pivotally mounted at 13 on a manipulator 14 the construction of which is Well known `in itself. The piston rod 12 is slidable in a cylinder 1S which is secured by bolts 16 to the peel of the manipulator, lpart of which peel is shown at 17. An end cover 18 is secured to one end of the peel by bolts 20 and has a sleeve portion 21 projecting into the bore of that end of the cylinder and an end portion 22 the bore of which has a smaller diameter than the bore `nf the. sleeve rmrh'm. o1 rnMm/l .u n

on the non-control side bearing against the stop surface 45 of the end cover 18 and stop surface 55 of the piston rod.

In operation, with the press on the right in FIGURE 1, and with forging taking place away from the press, when the bite occurs, so that the press tools contact the workpiece and the peel cannot move, the manipulator, carrying the piston rod, moves to the left in the figures, and can move relative to the peel to the position shown in FIGURE 2 for maximum recoil at the end of the press working stroke. During this movement the openings 47 and 48 are both open to drain. As shown in FIGURE 2 at the end of the maximum stroke away from the press the piston rod has moved relative to the cylinder and piston until the stop surface 55a engages the inner projections 60 of the surface 56. To return to the datum position the opening 48 is connected to a pressurized source, so that the pressure separates the faces 55a and 56 and drives the piston, cylinder, peel and workpiece to the left in the figures until the piston again abuts stop surface 55. FIGURE 3 shows the cylinder arrangement just before the datum position is regained. Hydraulic fluid is trapped in the annular space 57 and can only escape through opening 52 passage 53 and opening 54, and through the clearances between the rod and the protrusion 50. This restricted flow cushions the return.

FIGURE 4 shows the piston and cylinder arrangement after a maximum stroke when forging toward the press; in this position with both the openings 47 and 48 open to drain, the piston rod has moved to the right carrying with it the piston until the outer projections 60 of the piston abut stop surface 45a. The arrangement is again returned to its datum position by connecting opening 48 to a pressurized source which separates the surface 56 and 45a and drives the cylinder to the right in the figures. FIGURE 5 shows the arrangement when it has nearly regained its datum position from the FIGURE 4 position, in this case uid is trapped in the chamber 58 between the cylinder and the protrusion 50 and can only escape through the passage S3 which again produces a cushioning effect.

It is preferred, as described, that during the bite the control side of the cylinder is connected to exhaust, so that the manipulator drive motor does not work against any force other than the force caused by the hydraulic uid being displaced. In this case a control signal from the press position control at the end of a bite may be used to connect opening 48 to a pressurized source. Alter natively, the control side of the cylinder may be constantly connected to a pressure source so that it always biases the arrangement to its datum position. In this case no interlock with the press is required, the cylinder being connected with an accumulator and any oil losses from the circuit being catered for by means of a pressure switch and unloader valve, or a constant pressure 55 in the cylinder may be obtained by use of a relief valve to drain any excess of pressure build up.

By this arrangement forging may take place in either direction, a single control valve or no control valve is needed, mechanical stops automatically provide a datum position before such working stroke, and a built in cushioning device acts whether forging to or away from the press.

What is claimed is:

1. An assembly comprising a cylinder member encircling a piston rod member, a peel connected to one of said members, and a manipulator carriage connected to the other of said members, said piston rod being formed with a central portion of smaller diameter than portions of said rod nearer its ends so as to form a first pair of internally facing annular stop surfaces, and said cylinder being formed with a bore having a central portion of enlarged diameter so as to form a second pair of internally facing stop surfaces, and a piston slidable on the central portion of said rod between the stop surfaces on said rod and in said bore between the stop surfaces of said bore, said cylinder being connected on one side of the piston to exhaust and on the other side of said piston to a pressure source which automatically drives said piston, whenever said peel is free to move, into a position in which one face of said piston abuts a stop surface on said piston rod and a stop surface of said bore which are both on the same side of said piston and thereby locates said peel in a datum position relative to said carriage intermediate two extreme positions relative to said carriage, and said piston carrying an annular rib which projects beyond the cooperating stop surfaces against which said one piston face abuts when in said datum position, said rib having longitudinal surfaces which seal against an end portion of said piston rod and against said cylinder and being formed with a passageway extending from the free end of the rib to the inner surface of said rib near its base, through which fluid trapped between said one face of said piston and the cooperating stop on said piston rod may escape while cushioning the impact of said one piston face against said cooperating stop.

2. An assembly as claimed in claim 1 in which said pressure source is connected to said cylinder through valve means for connecting said other side of said cylinder alternatively to either said pressure source or to exhaust.

References Cited UNITED STATES PATENTS 845,827 3/ 1907 Steedman 92-85 1,845,797 2/ 1932 Kearney 92-52 2,649,842 8/ 1953 Caldwell et al. 92-52 3,250,247 5/1966 Beaman 92-129 X 3,274,819 9/1966 Knowles 72-421 3,279,563 10/ 1966 McNeeley 9-2-110` X MARTIN P. SCHWADRON, Primary Examiner.

I. C. COHEN, Assistant Examiner. 

